Generation system



April 3, 1951 w. F. FELL GENERATION sYs'rEu Original Filed 00?. 4, 1946 INVHVTOR.

WILL/AM E FELL flITOKA E Reissued Apr. 3, 1951 GENE I CATION SYSTEM William F. Fell, Hudson, Ohio, assignor to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Original No. 2,508,665, dated May 23, 1950, Serial No. 701,266, October 4, 1946.

Application for reissue August 31, 1950, Serial No. 182,569

6 Claims. (Cl. 171-119) Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification: matter printed in italics indicates the additions made by reissue.

Heretofore, in conventional generator systems,

if the potential coil of a carbon pile regulator for one of the generators should open or a short should occur across the carbon pile, there would occur an abnormal increase in the generator field current and hence an undesired increase in the output voltage.

An object of the present invention is to provide novel means effective for opening the generator field circuit in the event either of the aforenoted faults should occur.

Another object of the invention is to provide a novel system in which a circuit breaker opens the field circuit of the generator in response to an increase in the generator field current above a predetermined safe value, whereupon the voltage produced by this generator drops rapidly to zero.

Thus in the present system only the faulted generator ceases generating, whereas formerly in the conventional systems all the generators on the line would cease generating when any generator was faulted.

In the former system, when the output of one generator rose excessively in voltage, this would in turn cause the line voltage to increase to a value above the setting for line voltage circuit breakers for the other generators, where-upon the latte generators would in turn drop out. In the present invention, when one generator in the system is faulted, as described, and its field current rises, the regulators of the other generators tend to hold down the rise in line voltage for an appreciable length of time until the circuit breaker in the field circuit of the faulted generator opens.

An object of the present invention, therefore, is to provide an improved system for opening the field circuit of any one of the line generators when the field current rises above a predetermined value, so as to avoid the difiiculties aforenoted.

These and other objects and features of the invention are pointed out in the following description in terms of the embodiment thereof which is shown in the accompanying drawing. It is to be understood, however, that the drawing is for the purpose of illustration only, and is not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

The drawing is a schematic view of a generator system embodying the present invention.

Referring to the drawing, there is indicated by numerals l and 2 a pair of generators having field windings 3 and 4, respectively, and compensating field windings 5 and 6. The generators I and 2 may be of a conventional type and are connected through output lines 1 and 8, 9 and HI, respectively, to the main output lines I l and I2.

Controlling the output line I of the generator I is a line switch l3 which may be of any suitable type and controlling output line 9 of the generator 2 is a line switch It, which likewise may be of any suitable type.

The output line B of the generator I is grounded through connection l5 while the output line ill of the generator 2 is grounded through connection 16.

Leading from the output line 1 of the generator I is a line l8 which is connected to apotential coil l9 grounded at 20 and thus connected across the output lines I and 8 of the generator I.

The potential coil l5 controls an armature 2| biased under tension of a spring 22 so as to tend to compress a carbon pile 23 and thereby regulate the resistance of the pile 23 in a conventional manner.

The carbon pile 23 is preferably of a type such as shown in the copending appli:ation Serial No. 612,691, filed August 25, 1945, by William G. Neild, now U. S. Patent No. 2,481,771.

The carbon pile 23 is connected by a conductor 24 at one end to the line l8, while the opposite end of the carbon pile 23 is connected through a conductor 25 leading to a terminal 26 of a circuit breaker 21. An opposite terminal 28 of the circuit breaker 21 is connected by a conductor 29 to the field 3 of the generator I. Thus with the circuit breaker 21 in the closed position as shown, it will be seen that the carbon pile 23 will regulate the field 3 of the generator I in response to the output voltage across the lines 1 and 8 in the conventional manner.

The circuit breaker 21, however, is biased under tension of a spring 30 in an opening direction "and is held from opening by a latch 3| pivoted at h I! under tension 01 a spring 33 in a normallocking relation to the circuit breaker 21, and thereby holding the same in a circuit closing position. The latch 3| is controlled by electromagnetic winding it which is connected through conductor It to the line 25 and through a grounded connection it and circuit breaker 21 across the field windings I and 5 of the generator I.

Thus upon the field current through the winding 3 increasing above a predetermined maximum sate value eiiecting a corresponding increase in the voltage drop or fall of potential across the field winding I, the elect 3| will bias the latch ii in a counterclockwise direction permiting the circuit breaker 21 under tension of thespringil tomovetoacircuitopening position, whereupon the current fiow through the field winding 3 will cease andthe voltage produced by the generator I will drop rapidly to zero. Such excess current fiow may well occur upon either a shortage across the carbon pile regulator 23 or upon a short 0! the coil is causing an abnormal increase in the generator field current so as to cause in turn sufiicient energizetlon oi the circuit breaker winding 34 to eflect opening or the circuit breaker 21, whereupon the voltage produced by the generator will drop rapidly to zero.

A similar saiety provision is provided for the generator 2 in which like numerals having applied thereto the letter A, indicate corresponding parts to those described with reference to the generator I. While only two generators are shown, any desired number oi generators may be employed in the system.

It will be seen from the foregoing that there 7 has been provided a novel means for preventing over-voltage upon iailure of either the carbon pile regulator or the control coil theretor.

Although only one embodiment oi the invention has been illustrated and described, various changes in the form and relative arrangements or the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is, therefore, to be had to the appended claims for a definition oi the limits oi the invention.

What is claimed is:

1. In combination, [a load circuit,] a plurality oi generators having the outputs thereof connected in parallel, I: each of said generators having an output to said load circuit,] each of said generators having a field circuit including a field winding, a regulator associated with each of said field circuits, a control winding lor each of said regulators and connected across the output of its associated generator, a switch connected in the field circuit of each generator and control means for each oi said switches including a winding connected across the field winding oi the.

associated generator and efiective upon a rise in the voltage drop across the field winding above a predetermined sate value to open said switch and thereby its associated field circuit. while the regulator of the other oi said generators tends to maintain the voltage drop across the field winding of its associated generator below the predetermined sate value.

2. In combination, [a load circuit] a plurality oi generators [for said load circuit], having the outputs thereof connected in parallel, each of said generators having a field circuit including a field winding. a regulator associated with each oieaidfieldcircuimacontrolwindingioreaeh or said regulators and connected across the output 01 its associated generator, a switch connected in the field circuit of each generator, and control means for each oi said switches including spring means for biasing the switch in a circuit opening direction, latch means for locking the switch in a field circuit. closing position, and an electromagnetic winding connected across the field winding of the associated generator and eiiective upon a rise in the voltage drop across the field winding above a predetermined saie valus to bias said latch means so as to permit said spring means to actuate said switch to a field circuit open position while the switch 01' the other of said generators remains in the field circuit closing position, and the regulator of the other of said generators tends to maintain the voltage drop across the field winding of its associated generator below saidpredetermined sate value.

3. In combination, [a load circuit,] a generafor having an output [for said load circuit], a field circuit for said generator including a field winding, a regulator for said field circuit includ-- resistance of said carbon pile including acontrol winding connected across the output of the generator, a switch connected in the field circuit or the generator, and control means for said switch including spring means ior biasing the switch in a circuit opening direction, a latch for locking the switch in a field circuit closing position, and an electromagnetic winding connected across the field winding of the generator and effective upon a rise in the voltage drop across the field winding above a predetermined safe value as upon faults of the regulator to bias the latch in a direction so as to release said switch to open the field circuit.

4. In combination, [a load circuit,] a generator having an output [for said load circuit], a field circuit including a field winding for controlling the output of said generator, a switch connected in the field circuit of the generator and arranged to open and close the field circuit, control means for said switch including means for biasing the switch in a circuit opening direction, releasable means for locking the switch in a closed position, and an electromagnetic winding efiective upon a rise in the voltage drop across the field winding above a predetermined safe value for releasing the aforenoted locking means so as to cause said switch to open the field circuit.

5. In a multiple generator system, the com-'- blnation comprising a plurality of generators having the outputs thereof connected in parallel, [associated with] each of. said generators having a field circuit including a field winding and a regulator for said field winding; each of said regulators including a variable resistance element connected in the field circuit of the associated generator, and an electromagnetic means for varying the resistance of said element including a control winding connected across the output or the associated generator; the field circuit of each generator including a switch to control the field winding thereof, and an overvoltage coil connected across the field winding, said overvoltage coil responsive to the potential of the associated generator less the potential drop of the associated variable resistance element to operate said switch, said overvoltage coil responsive upon an increase in said operative potential above a predetermined 5 maximum safe value to actuate its associated opening of the switch of the field circuit of the switch so as to open the field circuit of the asone generator. eooiated generator and thereby prevent a faulty WILLIAM F. FELL. regulator of one generator from effectin an excessivc generator output and damage to the other 5 REFERENCES CITED said genemmm- The following references are of record in the 6. The combination defined by claim 5 in which file of this patent or the original patent: the non-faulty regulator of the other of said generators may elect a predetermined output condi- UNITED STATES PATENTS tion at said other 01' said generators uneflected 10 Number Name Date by the mum regulator, and means maint inin 1,238,145 Honold et a1 Aug. 28, 1917 the switch of the other of said generators in a 1,766,489 Creveling June 24, 1930 field circuit closing position irrespective of the 

